built-with-matrix-nio badge + permit aliases (#15)

* added built-with-matrix-nio badge to README

* permit aliases

- using room.is_group is not ideal to determine if a room is a DM
- if a room alias is created for a DM, the existing code will break
- changing to check for room.member_count seems to be more appropriate
- new code also works on DMs that have aliases

* moving badge next to existing badge

* Update my_project_name/callbacks.py

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

README.md

@@ -1,4 +1,4 @@
-# Nio Template <a href="https://matrix.to/#/#nio-template:matrix.org"><img src="https://img.shields.io/matrix/nio-template:matrix.org?color=blue&label=Join%20the%20Matrix%20Room&server_fqdn=matrix-client.matrix.org" /></a>
+# Nio Template [![Built with matrix-nio](https://img.shields.io/badge/built%20with-matrix--nio-brightgreen)](https://github.com/poljar/matrix-nio) <a href="https://matrix.to/#/#nio-template:matrix.org"><img src="https://img.shields.io/matrix/nio-template:matrix.org?color=blue&label=Join%20the%20Matrix%20Room&server_fqdn=matrix-client.matrix.org" /></a>
 
 A template for creating bots with
 [matrix-nio](https://github.com/poljar/matrix-nio). The documentation for

my_project_name/callbacks.py

@@ -46,7 +46,12 @@ class Callbacks(object):
 
         # Process as message if in a public room without command prefix
         has_command_prefix = msg.startswith(self.command_prefix)
-        if not has_command_prefix and not room.is_group:
+
+        # room.is_group is often a DM, but not always.
+        # room.is_group does not allow room aliases
+        # room.member_count > 2 ... we assume a public room
+        # room.member_count <= 2 ... we assume a DM
+        if not has_command_prefix and room.member_count > 2:
             # General message listener
             message = Message(self.client, self.store, self.config, msg, room, event)
             await message.process()